Gas turbine efficiency generally increases with the temperature of the combustion gas stream. Higher combustion gas stream temperatures, however, may produce higher levels of undesirable emissions such as nitrogen oxides (NOx) and the like. NOx emissions generally are subject to governmental regulations. Improved gas turbine efficiency therefore must be balanced with compliance with emissions regulations.
Lower NOx emission levels may be achieved by providing for good mixing of the fuel stream and the air stream. For example, the fuel stream and the air stream may be premixed in a Dry Low NOx (DLN) combustor before being admitted to a reaction or a combustion zone. Such premixing tends to reduce combustion temperatures and NOx emissions output.
In current micromixer designs, there may be multiple fuel feeds and/or liquid cartridge or blank feeds that obstruct air flow and decrease the mixing of fuel and air. Also, current micromixers are generally supported by external walls that inhibit air flow to the head end of the micromixer. Accordingly, there is a need for a micromixer that better facilitates fuel and air mixing.